180 research outputs found
The mean free path for electron conduction in metallic fullerenes
We calculate the electrical resistivity due to electron-phonon scattering for
a model of A3C60 (A= K, Rb), using an essentially exact quantum Monte-Carlo
calculation. In agreement with experiment, we obtain exceptionally large
metallic resistivities at large temperatures T. This illustrates that the
apparent mean free path can be much shorter than the separation of the
molecules. An interpretation of this result is given. The calculation also
explains the linear behavior in T at small T.Comment: 4 pages, RevTeX, 3 eps figure, additional material available at
http://www.mpi-stuttgart.mpg.de/docs/ANDERSEN/fullerene
Modulation of forebrain function by nucleus incertus and relaxin-3/RXFP3 signaling
This is the pre-peer reviewed version of the following article: Modulation of forebrain function by nucleus incertus and relaxinâ3/RXFP3 signaling, CNS neuroscience & therapeutics, 2018, vol. 24, no 8, p. 694-702, which has been published in final form at https://doi.org/10.1111/cns.12862. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.The nucleus incertus (NI) in the pontine tegmentum sends ascending projections to the midbrain, hypothalamus, amygdala, basal forebrain, hippocampus, and prefrontal cortex, and has a postulated role in modulating several forebrain functions. A substantial population of GABAergic NI neurons expresses the neuropeptide, relaxinâ3, which acts via the Gi/oâproteinâcoupled receptor, RXFP3, present throughout the forebrain target regions. Broad and specific manipulations of these systems by activation or inhibition of the NI or modulating RXFP3 signaling have revealed key insights into the likely influence of the NI/relaxinâ3/RXFP3 system on modalities including arousal, feeding, stress responses, anxiety and addiction, and attention and memory. This range of actions corresponds to a likely impact of NI/(relaxinâ3) projections on multiple integrated circuits, but makes it difficult to draw conclusions about a generalized function for this network. This review will focus on the key physiological process of oscillatory theta rhythm and the neural circuits that promote it during behavioral activation, highlighting the ability of NI and relaxinâ3/RXFP3 signaling systems to modulate these circuits. A better understanding of these mechanisms may provide a way to therapeutically adjust malfunction of forebrain activity present in several pathological conditions
L-lysine as adjunctive treatment in patients with schizophrenia: a single-blinded, randomized, cross-over pilot study
<p>Abstract</p> <p>Background</p> <p>Accumulating evidence suggests that the brain's nitric oxide (NO) signalling system may be involved in the pathophysiology of schizophrenia and could thus constitute a novel treatment target. The study was designed to investigate the benefit of L-lysine, an amino acid that interferes with NO production, as an add-on treatment for schizophrenia.</p> <p>Methods</p> <p>L-lysine, 6 g/day, was administered to 10 patients with schizophrenia as an adjunctive to their conventional antipsychotic medication. The study was designed as a single-blinded, cross-over study where patients were randomly assigned to initial treatment with either L-lysine or placebo and screened at baseline, after four weeks when treatment was crossed over, and after eight weeks.</p> <p>Results</p> <p>L-lysine treatment caused a significant increase in blood concentration of L-lysine and was well tolerated. A significant decrease in positive symptom severity, measured by the Positive And Negative Syndrome Scale (PANSS), was detected. A certain decrease in score was also observed during placebo treatment and the effects on PANSS could not unequivocally be assigned to the L-lysine treatment. Furthermore, performance on the Wisconsin Card Sorting Test was significantly improved compared to baseline, an effect probably biased by training. Subjective reports from three of the patients indicated decreased symptom severity and enhanced cognitive functioning.</p> <p>Conclusions</p> <p>Four-week L-lysine treatment of 6 g/day caused a significant increase in blood concentration of L-lysine that was well tolerated. Patients showed a significant decrease in positive symptoms as assessed by PANSS in addition to self-reported symptom improvement by three patients. The NO-signalling pathway is an interesting, potentially new treatment target for schizophrenia; however, the effects of L-lysine need further evaluation to decide the amino acid's potentially beneficial effects on symptom severity in schizophrenia.</p> <p>Trial registration</p> <p><a href="http://www.clinicaltrials.gov/ct2/show/NCT00996242">NCT00996242</a></p
Association between Polygenic Risk Scores and Outcome of ECT
Objective: Identifying biomarkers associated with response to electroconvulsive therapy (ECT) may aid clinical decisions. The authors examined whether greater polygenic liabilities for major depressive disorder, bipolar disorder, and schizophrenia are associated with improvement following ECT for a major depressive episode. Methods: Between 2013 and 2017, patients who had at least one treatment series recorded in the Swedish National Quality Register for ECT were invited to provide a blood sample for genotyping. The present study included 2,320 participants (median age, 51 years; 62.8% women) who had received an ECT series for a major depressive episode (77.1% unipolar depression), who had a registered treatment outcome, and whose polygenic risk scores (PRSs) could be calculated. Ordinal logistic regression was used to estimate the effect of PRS on Clinical Global Impressions improvement scale (CGI-I) score after each ECT series. Results: Greater PRS for major depressive disorder was significantly associated with less improvement on the CGI-I (odds ratio per standard deviation, 0.89, 95% CI=0.82, 0.96; R2= 0.004), and greater PRS for bipolar disorder was associated with greater improvement on theCGI-I (odds ratio per standard deviation, 1.14, 95% CI=1.05, 1.23; R2=0.005) after ECT. PRS for schizophrenia was not associated with improvement. In an overlapping sample (N=1,207) with data on response and remission derived fromthe self-ratedversion of theMontgomeryĂ
sberg Depression Rating Scale, resultswere similar except that schizophrenia PRS was also associated with remission. Conclusions: Improvement after ECT is associated with polygenic liability for major depressive disorder and bipolar disorder, providing evidence of a genetic component for ECT clinical response. These liabilitiesmay be considered alongwith clinical predictors in future predictionmodels of ECToutcomes
Genome-wide association study of patients with a severe major depressive episode treated with electroconvulsive therapy
Although large genome-wide association studies (GWAS) of major depressive disorder (MDD) have identified many significant loci, the SNP-based heritability remains notably low, which might be due to etiological heterogeneity in existing samples. Here, we test the utility of targeting the severe end of the MDD spectrum through genome-wide SNP genotyping of 2725 cases who received electroconvulsive therapy (ECT) for a major depressive episode (MDE) and 4035 controls. A subset of cases (n = 1796) met a narrow case definition (MDE occurring in the context of MDD). Standard GWAS quality control procedures and imputation were conducted. SNP heritability and genetic correlations with other traits were estimated using linkage disequilibrium score regression. Results were compared with MDD cases of mild-moderate severity receiving internet-based cognitive behavioral therapy (iCBT) and summary results from the Psychiatric Genomics Consortium (PGC). The SNP-based heritability was estimated at 29â34% (SE: 6%) for the narrow case definition, considerably higher than the 6.5â8.0% estimate in the most recent PGC MDD study. Our severe MDE cases had smaller genetic correlations with neurodevelopmental disorders and neuroticism than PGC MDD cases but higher genetic risk scores for bipolar disorder than iCBT MDD cases. One genome-wide significant locus was identified (rs114583506, P = 5eâ8) in an intron of HLA-B in the major histocompatibility locus on chr6. These results indicate that individuals receiving ECT for an MDE have higher burden of common variant risk loci than individuals with mild-moderate MDD. Furthermore, severe MDE shows stronger relations with other severe adult-onset psychiatric disorders but weaker relations with personality and stress-related traits than mild-moderate MDD. These findings suggest a different genetic architecture at the severest end of the spectrum, and support further study of the severest MDD cases as an extreme phenotype approach to understand the etiology of MDD
Understanding the context of balanced scorecard implementation: a hospital-based case study in pakistan
Background: As a response to a changing operating environment, healthcare administrators are implementing modern management tools in their organizations. The balanced scorecard (BSC) is considered a viable tool in high-income countries to improve hospital performance. The BSC has not been applied to hospital settings in low-income countries nor has the context for implementation been examined. This study explored contextual perspectives in relation to BSC implementation in a Pakistani hospital. Methods: Four clinical units of this hospital were involved in the BSC implementation based on their willingness to participate. Implementation included sensitization of units towards the BSC, developing specialty specific BSCs and reporting of performance based on the BSC during administrative meetings. Pettigrew and Whipp\u27s context (why), process (how) and content (what) framework of strategic change was used to guide data collection and analysis. Data collection methods included quantitative tools (a validated culture assessment questionnaire) and qualitative approaches including key informant interviews and participant observation.Results: Method triangulation provided common and contrasting results between the four units. A participatory culture, supportive leadership, financial and non-financial incentives, the presentation of clear direction by integrating support for the BSC in policies, resources, and routine activities emerged as desirable attributes for BSC implementation. The two units that lagged behind were more involved in direct inpatient care and carried a considerable clinical workload. Role clarification and consensus about the purpose and benefits of the BSC were noted as key strategies for overcoming implementation challenges in two clinical units that were relatively ahead in BSC implementation. It was noted that, rather than seeking to replace existing information systems, initiatives such as the BSC could be readily adopted if they are built on existing infrastructures and data networks. Conclusion: Variable levels of the BSC implementation were observed in this study. Those intending to apply the BSC in other hospital settings need to ensure a participatory culture, clear institutional mandate, appropriate leadership support, proper reward and recognition system, and sensitization to BSC benefits
Abnormality in glutamine-glutamate cycle in the cerebrospinal fluid of cognitively intact elderly individuals with major depressive disorder: a 3-year follow-up study
Major depressive disorder (MDD), common in the elderly, is a risk factor for dementia. Abnormalities in glutamatergic neurotransmission via the N-methyl-D-aspartate receptor (NMDA-R) have a key role in the pathophysiology of depression. This study examined whether depression was associated with cerebrospinal fluid (CSF) levels of NMDA-R neurotransmission-associated amino acids in cognitively intact elderly individuals with MDD and age- and gender-matched healthy controls. CSF was obtained from 47 volunteers (MDD group, N = 28; age- and gender-matched comparison group, N = 19) at baseline and 3-year follow-up (MDD group, N = 19; comparison group, N = 17). CSF levels of glutamine, glutamate, glycine, L-serine and D-serine were measured by highperformance liquid chromatography. CSF levels of amino acids did not differ across MDD and comparison groups. However, the ratio of glutamine to glutamate was significantly higher at baseline in subjects with MDD than in controls. The ratio decreased in individuals with MDD over the 3-year follow-up, and this decrease correlated with a decrease in the severity of depression. No correlations between absolute amino-acid levels and clinical variables were observed, nor were correlations between amino acids and other biomarkers (for example, amyloid-ÎČ42, amyloid-ÎČ40, and total and phosphorylated tau protein) detected. These results suggest that abnormalities in the glutamineâglutamate cycle in the communication between glia and neurons may have a role in the pathophysiology of depression in the elderly. Furthermore, the glutamine/glutamate ratio in CSF may be a state biomarker for depression
Insights into the innate immunity of the Mediterranean mussel Mytilus galloprovincialis
<p>Abstract</p> <p>Background</p> <p>Sessile bivalves of the genus <it>Mytilus </it>are suspension feeders relatively tolerant to a wide range of environmental changes, used as sentinels in ecotoxicological investigations and marketed worldwide as seafood. Mortality events caused by infective agents and parasites apparently occur less in mussels than in other bivalves but the molecular basis of such evidence is unknown. The arrangement of Mytibase, interactive catalogue of 7,112 transcripts of <it>M. galloprovincialis</it>, offered us the opportunity to look for gene sequences relevant to the host defences, in particular the innate immunity related genes.</p> <p>Results</p> <p>We have explored and described the Mytibase sequence clusters and singletons having a putative role in recognition, intracellular signalling, and neutralization of potential pathogens in <it>M. galloprovincialis</it>. Automatically assisted searches of protein signatures and manually cured sequence analysis confirmed the molecular diversity of recognition/effector molecules such as the antimicrobial peptides and many carbohydrate binding proteins. Molecular motifs identifying complement C1q, C-type lectins and fibrinogen-like transcripts emerged as the most abundant in the Mytibase collection whereas, conversely, sequence motifs denoting the regulatory cytokine MIF and cytokine-related transcripts represent singular and unexpected findings. Using a cross-search strategy, 1,820 putatively immune-related sequences were selected to design oligonucleotide probes and define a species-specific Immunochip (DNA microarray). The Immunochip performance was tested with hemolymph RNAs from mussels injected with <it>Vibrio splendidus </it>at 3 and 48 hours post-treatment. A total of 143 and 262 differentially expressed genes exemplify the early and late hemocyte response of the <it>Vibrio</it>-challenged mussels, respectively, with AMP trends confirmed by qPCR and clear modulation of interrelated signalling pathways.</p> <p>Conclusions</p> <p>The Mytibase collection is rich in gene transcripts modulated in response to antigenic stimuli and represents an interesting window for looking at the mussel immunome (transcriptomes mediating the mussel response to non-self or abnormal antigens). On this basis, we have defined a new microarray platform, a mussel Immunochip, as a flexible tool for the experimental validation of immune-candidate sequences, and tested its performance on <it>Vibrio</it>-activated mussel hemocytes. The microarray platform and related expression data can be regarded as a step forward in the study of the adaptive response of the <it>Mytilus </it>species to an evolving microbial world.</p
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Genomic and drug target evaluation of 90 cardiovascular proteins in 30,931 individuals.
Circulating proteins are vital in human health and disease and are frequently used as biomarkers for clinical decision-making or as targets for pharmacological intervention. Here, we map and replicate protein quantitative trait loci (pQTL) for 90 cardiovascular proteins in over 30,000 individuals, resulting in 451 pQTLs for 85 proteins. For each protein, we further perform pathway mapping to obtain trans-pQTL gene and regulatory designations. We substantiate these regulatory findings with orthogonal evidence for trans-pQTLs using mouse knockdown experiments (ABCA1 and TRIB1) and clinical trial results (chemokine receptors CCR2 and CCR5), with consistent regulation. Finally, we evaluate known drug targets, and suggest new target candidates or repositioning opportunities using Mendelian randomization. This identifies 11 proteins with causal evidence of involvement in human disease that have not previously been targeted, including EGF, IL-16, PAPPA, SPON1, F3, ADM, CASP-8, CHI3L1, CXCL16, GDF15 and MMP-12. Taken together, these findings demonstrate the utility of large-scale mapping of the genetics of the proteome and provide a resource for future precision studies of circulating proteins in human health
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